PT Unknown AU Schimmer, S Mittermüller, D Werner, T Görs, PE Meckelmann, S Finlay, DK Dittmer, U Littwitz-Salomon, E TI Fatty acids are crucial to fuel NK cells upon acute retrovirus infection PD 11 PY 2023 DI 10.3389/fimmu.2023.1296355 LA en DE NK cells; lipid metabolism; retrovirus; beta-oxidation; migration; fatty acids; cytotoxicity; CD36 AB Natural killer (NK) cells are cytotoxic innate immune cells, able to recognize and eliminate virus-infected as well as cancer cells. Metabolic reprogramming is crucial for their activity as they have enhanced energy and nutritional demands for their functions during an infection. Fatty acids (FAs) represent an important source of cellular energy and are essential for proliferation of immune cells. However, the precise role of FAs for NK cells activity in retrovirus infection was unknown. Here we show that activated NK cells increase the expression of the FA uptake receptor CD36 and subsequently the uptake of FAs upon acute virus infection. We found an enhanced flexibility of NK cells to utilize FAs as source of energy compare to naïve NK cells. NK cells that were able to generate energy from FAs showed an augmented target cell killing and increased expression of cytotoxic parameters. However, NK cells that were unable to generate energy from FAs exhibited a severely decreased migratory capacity. Our results demonstrate that NK cells require FAs in order to fight acute virus infection. Susceptibility to severe virus infections as it is shown for people with malnutrition may be augmented by defects in the FA processing machinery, which might be a target to therapeutically boost NK cell functions in the future. ER